# Another Five Numbers, 2: The Number Seven

## Possibly related…

1. ### The Number Four

Episode one of Another Five Numbers, the BBC radio series presented by Simon Singh.

Simon Singh's journey begins with the number 4, which for over a century has fuelled one of the most elusive problems in mathematics: is it true that any map can be coloured with just 4 colours so that no two neighbouring countries have the same colour? This question has tested some of the most imaginative minds — including Lewis Carroll's — and the eventual solution has aided the design of some of the world's most complex air and road networks.

2. ### A Countdown to Zero

Episode one of Five Numbers, the BBC radio series presented by Simon Singh.

What's 2 minus 2? The answer is obvious, right? But not if you wore a tunic, no socks and lived in Ancient Greece. For strange as it sounds, 'nothing' had to be invented, and then it took thousands of years to catch on.

3. ### 1 — The Most Popular Number

Episode one of A Further Five Numbers, the BBC radio series presented by Simon Singh.

Literally, the most popular number, as it appears more often than any other number. More specifically, the first digit of all numbers is a 1 about 30% of the time, whereas it is 9 just 4% of time. This was accidentally discovered by the engineer Frank Benford. It works for all numbers – mountain heights, river lengths, populations, etc.

4. ### 1 — The Most Popular Number

Episode one of A Further Five Numbers, the BBC radio series presented by Simon Singh.

Literally, the most popular number, as it appears more often than any other number. More specifically, the first digit of all numbers is a 1 about 30% of the time, whereas it is 9 just 4% of time. This was accidentally discovered by the engineer Frank Benford. It works for all numbers – mountain heights, river lengths, populations, etc.

5. ### Infinity

Episode five of Five Numbers, the BBC radio series presented by Simon Singh.

Given the old maxim about an infinite number of monkeys and typewriters, one can assume that said simian digits will type up the following line from Hamlet an infinite number of times.

6. ### Infinity

Episode five of Five Numbers, the BBC radio series presented by Simon Singh.

Given the old maxim about an infinite number of monkeys and typewriters, one can assume that said simian digits will type up the following line from Hamlet an infinite number of times.

7. ### The Imaginary Number

Episode four of Five Numbers, the BBC radio series presented by Simon Singh.

The imaginary number takes mathematics to another dimension. It was discovered in sixteenth century Italy at a time when being a mathematician was akin to being a modern day rock star, when there was 'nuff respect' to be had from solving a particularly 'wicked' equation. And the wicked equation of the day went like this: "If the square root of +1 is both +1 and -1, then what is the square root of -1?"

8. ### The Imaginary Number

Episode four of Five Numbers, the BBC radio series presented by Simon Singh.

The imaginary number takes mathematics to another dimension. It was discovered in sixteenth century Italy at a time when being a mathematician was akin to being a modern day rock star, when there was 'nuff respect' to be had from solving a particularly 'wicked' equation. And the wicked equation of the day went like this: "If the square root of 1 is both 1 and -1, then what is the square root of -1?"

9. ### Game Theory

Episode five of Another Five Numbers, the BBC radio series presented by Simon Singh.

In 2000, the UK government received a windfall of around £23 billion from its auction of third generation (3G) mobile phone licences. This astronomical sum wasn't the result of corporate bidders "losing their heads", but a careful strategy designed to maximise proceeds for the Treasury.

10. ### Game Theory

Episode five of Another Five Numbers, the BBC radio series presented by Simon Singh.

In 2000, the UK government received a windfall of around £23 billion from its auction of third generation (3G) mobile phone licences. This astronomical sum wasn't the result of corporate bidders "losing their heads", but a careful strategy designed to maximise proceeds for the Treasury.